Patent Document 1 discloses a conventional technology of a centrifugal pump. The centrifugal pump disclosed in Patent Document 1 includes an impeller driven by a motor to rotate, and the impeller is fixed to a shaft of a motor with a screw. When the impeller fixed to the shaft with the screw, the rotation of the shaft or the impeller needs to be limited such that the shaft does not rotate due to screw torque. In Patent Document 1, a fixation hole is formed in the impeller, and a jig is inserted into the fixation hole to limit the rotation of the impeller during screwing.